> I'va always wondered what people are using to measure interactivity. Do we have> some hard numbers from scheduler traces, or is it a "feels faster"?

I guess it's a "feels faster", because it's the only thing thatcounts. Given that there is strong evidence that scheduler A is"faster, more interactive", whatever... than scheduler B, but acontrolled trial shows a significantly better "feels faster"experience using scheduler B, I'm quite shure that people would choosescheduler B over A, and that's quite ok. It does what they expect itto do, despite evidence which documents the opposite.

> And if it's a subjective thing, how are people avoiding confirmation bias (where you> decide it feels faster because it's the new kernel and *should* feel faster)?

Confirmation bias is one thing, and it does exist. Surely. So it's upto the user if it wants evidence, or if it's enough that it feelsfaster. I guess that evidence doesn't really matter for the most ofthe users as long as they have a positive experience.

> Anybody doing blinded boots, where a random kernel old/new is booted and the> user grades the performance without knowing which one was actually running?

Hey, we could construct a randomized controlled trial on this :-)

> And yes, this can be a real issue - anybody who's been a aysadmin for> a while will have at least one story of scheduling an upgrade, scratching it> at the last minute, and then having users complain about how the upgrade> ruined performance and introduced bugs...

Yep. They who have to do "real work" will rather base it on evidencethan trust their own feelings.